Movin On Out

Duxbury Bay has been pretty cold this spring, which has delayed our ability to put the oyster babies out in the water. In the hatchery, the oyster larvae are grown in water that is heated to 78 degrees. Once they are big enough, they can tolerate colder water. Then when the bay temperature reaches the mid-50’s, the big oysters can move outside into our downweller system. This system pulls bay water directly into a tank out on our deck, cycles through the screens, and back out to the bay. The oysters are constantly feeding on algae that are natural to Duxbury Bay, so they can eat all they want!

For the past month or so, we’ve been sending out all our oysters that are 1 millimeter in size. The smaller ones remain in the hatchery until they have grown big enough. Within the past couple weeks; the temperature has increased to the mid-60’s, so we can put out even smaller oysters, about half a millimeter, as they will continue to grow in the warm water.

The oyster seed will grow in the downweller for a week or so until they reach 1.5 millimeters. At this stage in their life, they move into the flupsys, or upwellers, under the dock. This system is the same idea as the downweller except the water flows in the opposite direction, up, giving the oysters better flow. As the bay gets warmer and warmer throughout the summer, the oysters spend less time in the hatchery because they can tolerate the warm and unfiltered bay water. It is important for us to grade the oysters frequently, just like we grade the larvae in the hatchery. In other words, we stack up some sieves and rinse down the seed to figure out who is what size. That way, we can then separate the “macho oysters” from the slower-growing oysters. We will continue this process for the rest of the hatchery season until all of our oysters are all grown up!

Our seed is growing strong and fast, due to the big tides that flow in and out of Duxbury Bay twice a day. The new water brought in with the tide is always full of rich nutrients and thousands of species of algae. The more algae available to them, the more they eat, the faster they grow, and the sooner they end up on your plate! The oysters are living large eating up all the food and soaking in the warm water!

 

★ Hannah Pearson is the lead Hatchery Technician at Island Creek. She hates gluten. ★